1. Field of the Invention
The present invention relates to an automated analyzer for assaying a specific component in a sample. More particularly, the present invention relates to an automated analyzer for assaying a specific component in a sample by using a vessel which contains reagents therein.
2. Description of the Related Art
In recent years, automated analyzers are utilized in a variety of application fields. For example, an immunoassay apparatus for assaying an antigen or an antibody in a sample such as blood, plasma, and the like by utilizing an antigen or an antibody is utilized in a clinical diagnostic field.
In this specification, the present invention is described, as an example, regarding an immunoassay apparatus, particularly an automatic analyzer for conducting enzyme immunoassay by use of an enzyme-labelled antibody (or antigen). (Hereinafter the term "enzyme immunoassay" is referred to as "EIA".)
The EIA is a method for assaying a small amount of a component in a sample (Clinical Chemistry, Vol. 22, No. 8, 1243-1255, 1976). In a sandwich method therefor, the specific component to be assayed is captured by an appropriate antibody (or antigen) immobilized on a suitable solid phase material; then an enzyme-linked antibody or antigen (a conjugate) capable of reacting with the component to be assayed is brought into contact therewith to form an immune complex; the excess of the conjugate is removed; a substrate is added thereto which will output a detectable signal (such as change of absorbance, change of fluorescence intensity, etc.) by an activity of the enzyme; the signal is measured to determine quantitatively the amount of the enzyme according to a preliminarily prepared calibration curve; and from this the quantity of the specified component is estimated.
In this method, since different reagents, namely antibodies or antigens, are required corresponding to specific components to be assayed, the reaction vessels are provided in which different reagents are sealed up respectively corresponding to the specific components to be assayed, and are appropriately selected and used.
One of the example of automated analyzers for EIA is described in JP-A-62-148858 (The term "JP-A" as used herein means an "unexamined laid-open Japanese patent publication"), which comprises; means for dispensing a sample, means for breaking the top seal of a reaction vessel, means for dispensing a substrate, means for measuring, means for transferring reaction vessels.
In case where the concentration of the specific component is extremely high or extremely low, the detection ability of the reagent sealed in a reaction vessel is, usually, preliminarily adjusted to cover a wide range concentration of the specific component, or otherwise sample volume is adjusted according to the analyte.
In other words, conventionally, the assay is performed at a fixed sample volume for analytes which can be assayed at the sample volume, and thereafter the assay is performed for other analytes regarding the same or different samples at different sample volume.
In another practice, for the purpose of avoiding a repetition of the assay regarding the same sample, the sample volume is changed for every analyte by using an external input device such as a keyboard.
However, it is not desirable to perform the assay firstly for selected analytes for which the same sample volume is acceptable and then to perform the assay for other analytes for which a different sample volume is acceptable, because such operation takes much time and at least one operator have to be engaged therein. Further, the input operation of sample volumes by an external device for respective analytes requires at least one operator and artificial input errors may cause serious mistakes to assay results. These are the disadvantages which are to be solved by the present invention.